The present invention relates to upper internal equipments for a nuclear reactor, and it is particularly applicable to reactors that are cooled and moderated by pressurized water.
More particularly, it relates to internal equipments located above the core of a nuclear reactor, the equipment comprising a bottom plate formed with openings allowing coolant to leave the core, a top plate, spacer columns interconnecting the plates, and cluster guides for control clusters that are vertically displaceable between a lower position in which they are inserted in the core and an upper position in which they are out of the core, at least some of the guides each having an upper length that projects above the top plate and a bottom length that extends between the plates and that is within a respective spacer column.
In general, the top length of each cluster guide includes a tube along which cross plates are distributed for guiding individual rods, and the bottom lengths include split tubes each allocated to one rod and sleeves each allocated to two rods.
Equipments of this kind are described, for example, in U.S. Pat. No. 5,183,628.